Electronic timepiece

ABSTRACT

AN ELECTRONIC TIMEPIECE COMPRISES A TIME BASE DELIVERING HIGH FREQUENCY ELECTRIC SIGNALS AND ELECTRONIC MEANS FOR DIVIDING THIS HIGH FREQUENCY, AND TIME-REPRESENTING MEMBERS, WHEREIN A DEVICE IS PROVIDED FOR CORRECTING THE TIME GIVEN BY THE TIME-REPRESENTING MEMBERS WHEN THE TIME DOES NOT CORRESPOND TO THAT WHICH IT SHOULD ACTUALLY BE ON THE BASIS OF A COUNT OF THE SIGNALS OF DIVIDED FREQUENCY ISSUING FROM THE DIVIDING MEANS.

ELECTRONIC TIMEPIECE Jan 32, in

5 Sheets-Sheet 1 Filed Feb. 12, 1969 8 Sec ELECTRONIC TIMEPIE'CE 5Sheets-Sheet a Filed Feb; 12, 1969 UUUUUUUU VD 2O Jan. 1 2, 1971 RDQEETAL ELECTRONIC TIMEPIECE 5 Sheets-Sheet 5 Filed Feb. 12, 1969 ONQUnited States Patent O T Int. ci. G04c 3/00 US. Cl. 58-23 4 ClaimsABSTRACT OF THE DISCLOSURE An electronic timepiece comprises a time basedelivering high frequency electric signals and electronic means fordividing this high frequency, and time-representing members, wherein adevice is provided for correcting the time given by thetime-representing members when the time does not correspond to thatwhich it should actually be on the basis of a count of the signals ofdivided frequency issuing from the dividing means.

CROSS-REFERENCES TO RELATED APPLICATIONS This application is acontinuation-in-part of our application Ser. No. 614,937, filed Feb. 9,1967, which is now abandoned.

BACKGROUND OF THE INVENTION There are in existence electronictimepieces, e.g. clocks, pocket watches and even wrist watches, havingan accuracy which is far greater than that achieved with time pieceswhich are purely mechanically operated or which are evenelectromechanically operated.

In some of these electronic timepieces, in particular clocks comprisinga time base delivering time signals of well-defined frequency, andfurther comprising electronic means for dividing this frequency andtime-indi eating means controlled by the signals of divided fre quencyissuing from the frequency dividing means, accuracy is achieved with thehelp of a master-clock periodically connected up to the timepiece per seand of a zero resetting device driven by the master-clock and serving tomodify the time given by the time-indicating means to agree with thatgiven by the master-clock.

In other electronic timepieces, in particular light-weight transportableones, such as pocket watches and wrist watches, accuracy is whollydependent on the time base that is resorted to. There are in existencesome exceptionally accurate time bases, e.g. quartz oscillators andtuning fork oscillators, which can readily be set to a desired constantfrequency and whose steadiness of operation can be kept upnotwithstanding quite substantial variations in temperature. In suchtimepieces, the greatest source of error is thus caused by defectsassociated with their time-indicating device.

In particular, when this time-indicating device includes anelectromechanical converter controlled by the impulses issuing from thedividing means, the above defects are closely tied to the relativeinsensitiveness of the converter to the parasitic influences to which itcan be subjected, e.g. acceleration and outside magretic fields.

Consequently, in an electronically operating timepiece having a timebase delivering high frequency periodic signals, means for dividing thisfrequency and a time indicating device including such a converter, animprovement of its accuray is possible only if particular care is givento the construction of the time-indicating Patented Jan. 12, 1971 deviceand this cannot be achieved without resorting to highly skilled labourand to costly constructional techniques that are diflicult to put intoeifect.

SUMMARY OF THE INVENTION The present invention seeks to obviate thevarious drawbacks mentioned above and provides an electronic timepiececomprising a time base delivering high frequency electric signals;electronic means for dividing said frequency which includes a successionof dividing stages; a time-indicating device which includestime-representing members and which is controlled by the signals ofdivided frequency issuing from the dividing means; and a timesettingdevice; wherein is provided a correcting device which includes means forperiodically detecting any positional deflection of saidtime-representing members in relation to a reference positioncorresponding to that which these members should be occupying at theinstant of detection on the basis of a count of the signals issuing fromthe dividing means, means for producing a signal indicative of thedirection of said deflection, means for momentarily connecting thetime-indicating device to an intermediate stage of said dividing means,when said indicative signal indicates a lag on the part of saidtimerepresenting members, thereby to accelerate the operation of saiddevice to make up said lag, and means for momentarily interrupting allconnection between the dividing means and the time-indicating device,when said indicative signal indicates a lead on the part of saidtime-representing members, thereby to cut out this lead through stoppageof said device.

BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings:

FIG. 1 is a block diagram illustrating the principle of operation of anelectronic timepiece according to the invention;

FIG. 2 is a plan view of the movement of the timepiece shown in FIG. 1,here assumed to be a wrist-watch;

FIG. 3 is a section along line III-III of FIG. 2;

FIG. 4 is an electric diagram of an electronic frequency divider for thetimepiece shown in FIG. 1;

FIGS. 5, 6, and 7 are diagrams of three stages of the frequency dividershown in FIG. 5;

FIG. 8 is a plan view of an electromechanical converter of monostabletype for the timepiece shown in FIG. 1;

FIG. 9 is an electric diagram of a control circuit for the convertershown in FIG. 8;

FIG. 10 shows a number of oscillograms for explaining the operation ofthe circuit represented in FIG. 9;

FIG. 11 is a functional diagram of a device for correcting the timeindication given by the timepiece of FIGS. 1 to 3; and

FIG. 12 shows a number of oscillograms for explaining the operation ofthe device represented in FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENT The electronic watch, whoseconstructional features are visible in FIGS. 2 and 3, diagrammaticallyis as shown in FIG. 1. It comprises a quartz oscillator O which deliversa high frequency periodic signal V0 to an electronic divider DM Whoseconstructional details will be described later. This divider DM dividesthe relatively high frequency of the signals V0 which it converts intoimpulses of relatively low frequency, e.g. 1 c./s., to form signals V0that are fed to a time-indicating device IT comprising anelectromagnetic converter Rb, together with a control circuit ERtherefor, and further comprising a train of three wheels s, m and h fordriving hands As, Am and Ah for the seconds, minutes, and hours,respectively (FIG. 2). The illustrated watch comprises moreover a deviceGP for correcting the position of the train of wheels s, m, h. Thisdevice is connected to the divider DM, from which it periodicallyreceives a checking Signal Sc, and to a detector cooperating with awheel which is kinematically associated with the train s, m, h andsupplying a signal SI indicative of the position of this wheel at theinstant signal Sc is received. Moreover, device CP delivers a correctionsignal Scc to the converter Rb via its control circuit ER. The exactcorrection procedure, which consists in periodically moving the train s,m, h from its actual position to that it should have been occupying onthe basis of a count of the periodic signals produced by oscillatorsince the previous correction operation, will be described in detailfurther on.

The oscillator O, the divider DM and the device IT are supplied withelectric power of a source P (FIG. 1) consisting of two cells P1 and P2connected in series (FIG. 2).

The electronic circuit OA of oscillator O, the electronic circuits EA,EB and EC of divider DM, the electronic circuit CC of correctionarrangement CP, and the electronic circuit ER of converter Rb, were hereall integrated and mounted on a common base Su, these circuits beingsuitably connected to one another and being further connected to cellsP1 and P2, by electrical connections not shown.

:The quartz crystal Q of the oscillator is encapsulated, together withits electrodes, in a block of insulating material and is positionedbeneath a winding Lo (FIGS. 2 and 3) forming an integral part of theoscillator. The oscillator circuit 0A may, for instance, be similar tothat described in Canadian Pat. No. 791,946.

The electromagnetic converter Rb, the details of which will be describedlater, serves to drive, by alternate ratcheting engagement, a toothedwheel 1 (FIG. 2) on whose pin is keyed a pinion 2. meshing with atoothed disc 3. Disc 3 meshes with the second wheels and drives a pinion4 meshing with the minutes wheel m.

This wheel m is solid with a tube 5 (FIG. 3) which is rotatably mountedon the pin 6 of wheel s and whose lower end broadens out to form apinion 7 meshing with the hours wheel h, through the intermediary of atoothed disc 8, a pin 9 and a pinion 10.

Time setting of the illustrated watch by the user can be done by meansof a device MH which acts on the disc 8 and which can be operated fromthe outside of the watch by suitable actuating means not shown.

As already mentioned, the illustrated watch comprises moreover a deviceCP for correcting the position of the train of wheels s, m, h, and thisdevice is wholly independent of the above referred to time settingdevice MH. FIGS. 2 and 3 show, in addition to the electronic circuit CC,the electromechanical components of device CP, i.e. a checking disc kmounted on a pivotal pin 11 and rotated, via a transmission not shown,off the watch wheel train so as to carry out one revolution everysixtyfour seconds. On its periphery, disc k defines a pair of lugs v1and v2 forming two mobile electrodes which alternately pass, twice everysixty-four seconds, opposite two stationary electrodes sel and se2 whichare connected to circuit CC in a manner to be described later. Anotherelectrode q, intended to form a capacitive coupling with disc k, issecured to the support Su, at a small distance from this disc, so aspermanently to overlap a portion thereof.

The oscillator 0 comprises a resonator having a particularly highquality factor, here an At cut quartz. This quartz has a particularlyhigh frequency, here a frequency of 5 mc./s. By way of modification, theoscillator could of course include a resonator of a dilferent type, suchas an acoustic vibrator of the tuning-fork kind.

The frequency divider shown in FIG. 4 comprises twenty-one stages ofthree different types, EA (FIG. 5), EB (FIG. 6), and EC (FIG. 7), inparticular a first stage EA1 for dividing high frequency signals, tenstages BB2 to EB11 for dividing high and medium frequency signals, andten stages EC12 to EC21 for dividing low frequency signals.

As is apparent from FIG. 4, stage EA1 comprises two inputs el and f1which are respectively connected to the negative pole of source P, via aresistor R, and to the output s of the oscillator 0. Stage EA1 furthercomprises two outputs b1 and 01 which are respectively connected to thegates of two transistors Td1 and Td2 which are connected in series tothe poles of source P and which form a decoupling circuit. The output ofthis decoupling circuit is connected, on the one hand, to the input, f2,of the following stage BB2 and, on the other hand, to a supply line LA.The ten stages EBZ to EB11, which are all of the type shown in FIG. 6,comprise each an output, respectively d2 to dll, and are separated by adecoupling circuit consisting of three transistors Td3, Td4 and Td5, andof a capacitor Cd3. As will be observed in FIG. 4, Td3 and Cd3 areconnected in series to the supply line LA and Td4 and Td5 are connectedin series to source P. The outputs d2 to d11 of stages BB2 to EB11 aremoreover connected to the gates of transistors Td3 and Td5 of thedecoupling circuit associated with the following EB stage. A secondsupply line LA is connected to the input of stage EB11.

The ten stages EC12 to EC21, which are all of the type shown in FIG. 7,comprise each a first input, respectively g12 to g21, connected tosupply line LA and a second input, respectively -]12 to 21, connected tothe output of a decoupling circuit separating each EC stage from thepreceding stage. Each of the decoupling circuits preceding stages EC13to EC21, as well as an identical decoupling circuit following stage EC21comprises two transistors Tdfi and Td7 each connected, in series with acapacitor Cd6 and Cd7, respectively, to the line LA, the gate of Td7being connected to the output of Td6 and the gate of Td6 being connectedto the output, a12 to (121, respectively of the preceding EC stages. Asfor the decoupled circuit separating stage EB11 from stage EC12, it onlycomprises a capacitor Q16 and a transistor Td6.

The operation of each type of dividing stage EA, EB and EC, illustratedin FIGS. 5 to 7, is already described in detail in the specification ofCanadian Pat. No. 791,946 and in the specification of US. Pat. No.3,383,570 and will not therefore be repeated here. Suflice it simply tosay that with stage EA1 (FIG. 5) the frequency of the voltage impulsesdelivered at the output terminal c1 is one fourth the frequency of theinput signals Vo received from the oscillator O at input 7'1; with theEB and EC stages the frequency of their input signal is divided by two.

The operation of the FIG. 4 divider as a whole is practically identicalto that of the divider described in the above mentioned patentspecification to which reference should be made for further particulars.Be it simply stated that the FIG. 4 divider delivers at its output onesignal per second (F =1 c./s.) and that this signal is used, asdescribed, to control the electromechanical converter of the timepiece,which converter serves to drive the gear train s, m, h and the handsassociated therewith. This converter is represented in FIG. 8 in theform of a monostable relay driving one of the gears of the train; by wayof variant it can also consist of a bistable relay or even of a steppingmotor.

The FIG. 8 relay, which is of the monostable type, comprises a mobilearmature consisting of an anchor 12 which is carried by a pin 13pivotally mounted in the base of the movement (FIG. 3) and whichalternately engages, by means of bladees 13a and 13b, the teeth ofwheel 1. The shank of anchor 12 carries two small plates 14s and Mnconsisting of permanent magnets so oriented as to form a single magneticcircuit. This relay also comprises an energizing winding R6, forming athin, fiat member, and a magnetic stop 15 defining the only stableposition for anchor 12 when current flow of the winding R6 isinterrupted, this position being attained under the action of the pullexerted by the magnetic leakage flux and tending to reduce the air gapbetween stop and magnet 1412 to a minimum.

The described relay is conctrolled by the FIG. 9 circuit which includesthe above mentioned winding R6 and which is connected to the FIG. 4divider at the output a21 of stage EC21 and at point b" of stage EC,this latter point being indicated in FIG. 7 and being identified as 1120in'FIG. 9.

The relay control circuit comprises, in addition to the winding R6, twotransistors Te1'6 and Te17 which are series connected to source -P and athird transistor Tel8 which is connected to this same source P in serieswith the winding R6 and whose gate is connected to the point ofinterconnection between Tel6 and Te17. A capacitor Cell is connected inparallel with Te16.

The operation of the FIG. 9 circuit will now be described with referenceto the FIG. 10 oscillograms respectively showing the evolution of thefollowing voltages:

Vg'the voltage in the general supply line LA for the EC stages of thedivider shown in FIG. 4;

Vfl9--the voltage at the input terminal 1 of the divider stage E'Cl9;

V1119, V1120 and Va2l-the voltages at the output of the first transistor(Tel, point a", FIG. 7) of the divider stages EC19, EC20 and EC21respectively;

Vb20-the voltage at point b (FIG. 7) of the divider stage EC20;

Vm-the voltage at point In of the FIG. 9 circuit; and

Vi-the voltage at point z of the FIG 9 circuit.

In the case illustrated in FIG. 10, it was assumed that the voltageimpulses required to actuate the relay, i.e. Vi, had to have the samefrequency as signal Va21 at the output of the divider, but had to beeight times longer in duration than the impulses of the general supplyvoltage Vg'. That is why the gate of transistor Te17 is connected topoint b" of stage EC20, and that of transistor Te16 is connected to theoutput terminal a2l of stage EC21.

The impulses of signal Vb20 render Tel7 conductive and thus enablecapacitor Cell to be charged by source P. The control voltage of Tel8 isthus practically nil and Tel8 consequently remains blocked. When theimpulses of signal Va2l appear there are no signal V1220 impulses (seeFIG. 10) at the gate of Tel7 which ceases to be conductive; capacitorCell then discharges through Te16 since the latter is conductive.Provided the duration of the control impulse for Tel6 (signal Va21) issufficiently long for Cell discharge Within the desired time limits,Tel8 will become conductive and current will thus be able to flowthrough the relay actuating winding R6. Cell will remain dischargeduntil the appearance of the next signal Vb20 impulse, which impulsecauses Cell to be charged again and hence Tel8 to be blocked; no currentcan then flow through winding R6;

As mentioned earlier, the described watch includes a device CP forcorrecting the position of the train of wheels (FIG. 1) and theelectromechanical features of this device have already been describedwith reference to FIGS. 2 and 3.

This device operates as follows: the position of the wheel train isperiodically detected by means of a signal produced by additionaldividing stages connected to the output terminals of the FIG. 4 dividerand a check is then made to determine whether or not the detectionsignal coincides with a reference signal corresponding to the positionthat the wheel train should in fact be occupying were the relay drivingthe wheel train correctly. Should a positional error be detected, acorrection circuit comes to act on the time indicating device to correctits position and thus avoid any accumulation, over a long period oftime, of counting errors. These positional errors of the wheel train maybe due, for instance, to parasitic accelerations or to the influence ofoutside magnetic fields, causing incorrect actuation of the relayarmature.

A suitable correcting device is shown in FIG. 11. In this figure is tobe found again the checking disc k which is so driven by the wheel trainof the watch as to carry out one revolution every 64 seconds. As statedpreviously, disc k is provided at its periphery with two diametricallyopposite radially-projecting lugs v1 and v2 which form two mobileelesctrodes intended to cooperate with two stationary electrodes sel andse2.

These stationary electrodes sel and se2 extend over an angular distancewhich corresponds at least to two successive intermittent displacementof disc k and are each connected to a capacitor and to a transistormounted in series, i.e. C12 and T19, and C13 and T20, respectively.

Between each stationary electrode, respectively sel and' se2, and theassociated capacitor, respectively C12 and C13, the circuit comprises anohmic contact, respectively j1 and 2, which is formed on a p-type zonediffused into an n-type base and which determines the potential of thecorresponding circuit section. As may be seen from FIG. 11, the gate oftransistor T19 is connected to contact '2 and the gate of transistor T20is connected to contact jl.

FIG. 11 also shows several frequency dividing stages, to wit EC20 toEC26, of which stages EC20 and EC21 are, here, the last two stages ofthe divider shown in FIG. 4. The five additional stages EC22 to EC26serve to divide the repetition frequency of l c./s. at the output a21 ofstage EC21 to a frequency of A c./s. at the output a26 of stage EC26.Stages EC22 to EC26 are also each provided with a decoupling circuit ofthe type shown in FIG. 4, but these circuits have been omitted from FIG.11 in order to simplify the drawing.

The correcting circuit further comprises two transistors T21 and T22respectively connected, in series with capacitors C14 and C15respectively, to the output terminals a20 and a21 of the last two stages(EC20 and EC21) for the divider. The gates of T21 and T22 arerespectively connected to the outputs of T20 and T19. This circuitmoreover includes an actuating circuit R6, T26, C16, T24, T23 for themonostable relay Rb, which actuating circuit corresponds to that shownin FIG. 9. The gate of T23 is connected to the output [220 of stage EC20whereas the gate of T24 is connected to the output of T22. A transistorT25 is connected, in parallel with C16, between the negative pole ofsource P and the input of T26. The circuit furthermore comprises atransistor T27 connected, in series with a capacitor C17, to the outputof stage EC20, the gate of T27 being connected to the output of T21 andthe output of T27 being connected to the gate of T25. In addition, thecircuit comprises a transistor T29 connected, in series with a capacitorC18, to the source P, the output of T29 (point 0) being connected to theelectrode q (FIGS. 2 and 11). A transistor T28 is connected between thenegative pole of source P and point 0, the gate of T28 being connectedto the output a26 of additional dividing stage EC26. As is apparent fromFIG. 11, a capacitor C19 is connected between the negative pole ofsource P and the gate (point n) of T29. Further, two transistors T30 andT31 are connected, in series, to source P, the output of T31 beingconnected to the gate of T29. The circuit finally comprises a transistorT32 connected, in series with a capacitor C20, to the output a21 ofdivider stage EC21, the output of T32 being connected to the gate ofT30, whereas the gates of T31 and T32 are connected to the output a26 ofstage EC26.

Positional checking of the wheel train is carried out at time intervalsof thirty-two seconds through the intermediary of a signal Vq supplyingthe coupling electrode q, and the duration of this signal determines thedetection and correction period.

It will now be explained how this signal Vq is obtained. For this, itwill be assumed that, upon impulses of signals Va21 and Va26 beingsimultaneously emitted by the respective dividing stages (FIG. 12),capacitor C18 is charged, capacitor C19 is discharged, transistor T29 isopen, so that electrode q is at zero potential (Vq=), and transistorsT28,T30, T31 and T32 are blocked.

When an impulse of signal Va26 appears in synchronism with an impulse ofsignal Va21, transistors T28, T31 and T32 become conductive so that:

(1) Capacitor C18 discharges thus causing point 0 and electrode q todrop to the same negative potential as source P (formation stage of thefront of an impulse Vq, FIG. 12);

(2) The signal Va21 impulse is earthed via transistor T32, transistorT30 remains blocked and capacitor C19 can be charged by the currentflowing through transistor T31; and

(3) Once capacitor C19 is charged, point n acquires zero potential andtransistor T29 becomes blocked.

As soon as this impulse of signal Va26 ends, transistors T28, T31 andT32 become blocked again and the circuit for forming signal Vq remainsin this condition, with capacitor C18 discharged and capacitor 019charged, until the arrival of the next impulse of signal Va21, onesecond after the first, to which there will obviously be nocorresponding impulse of signal Va26 since the latter has a lesserfrequency in fact thirty-two times less.

This means that:

(1) Capacitor C19 discharges; and

(2) Transistor T29 becomes blocked again, the potential at point 0becomes zero and capacitor C18 becomes charged so that electrode q,which had been kept at the negative potential of source P, is now raisedto zero potential.

The alternate charging and discharging of capacitors C18 and C19 thusenables the production of a voltage impulse to form signal Vq, whichimpu se has a duration corresponding to the repetition period of theimpulses of signal Va21, in this instance one second, the repetitionperiod of the signal Vq impulses corresponding to that of the signalVa26 impulses, i.e. thirty-two seconds in the described embodiment.

During assembly of the watch, disc k is positioned in an angularposition such that the mobile electrodes v1 and v2 will overlap thestationary electrodes sel and se2 when electrode q receives a signal Vqimpulse (axis Z1Z1). If the wheel train is correctly driven by the relay, i.e. if disc k does in fact carry out one revolution everysixty-four seconds electrode q will be receiving two signal Vq impulsesper revolution of the disc, to wit one when the mobile electrodes ofdisc k come to occupy the illustrated position and a second when theseelectrodes will have moved on through 180.

If disc k is assumed to be rotating in an anti-clockwise direction, andif its electrodes v1 and v2 should happen to be lying on axis Z2Z2 whenelectrode q receives a signal Vq impulse, this would mean that the wheeltrain is leading in relation to reference position Z1Z1, i.e. theposition the wheel train should be occupying on the basis of a count ofimpulses Vm received \by relay Rb.

But it the electrodes v1 and v2 of disc k should happen to by lying onaxis Z3-Z3 when electrod q receives a signal Vq impulse, this would meanthat the wheel train is lagging in relation to reference position Z1Z1.

It will now be explained how the position of disc k can be detected whena checking impulse Vq reaches electrode q and how the correcting deviceof the watch reacts to this detection.

(A) CORRECT WORKING OF THE WATCH Disc k is assumed to be occupying theposition shown in FIG. 11. Thus, when a signal Vq impulse iscapacitively received from electrode q, it will be retransmitted,capacitively also, to the stationary electrodes se1 and se2. The gatesof transistors T19 and T20, respectively connected to contacts 12 andjl, thus receive a negative potential and these transistors then becomeconductive. Consequently, capacitors C12 and C13 become charged and thepotential of gates of transistors T21 and T22 becomes zero so that thesetransistors remain blocked.

Since T21 is blocked, the impulses of signal Va20, coming from output ofstage EC20, can reach the gate of T27 and the latter, through havingbecome conductive, prevents these self-same impulses from reaching thegate of T25 so that this latter transistor remains blocked.

The impulses of signal Va21 and those of signal Vb20 can thus freelysupply the control circuit of relay Rb which produces signal Vmv andwhich is made up of tran sistors T23, T24 and T 26 and of capacitor C16as already described. The monostable relay is thus driven in therequired manner.

(B) THE WHEEL TRAIN OF THE WATCH COMES TO BE LEADING Should the wheeltrain of the watch comes to be leading, disc k would come to lie forexample, in a position such that its electrodes v1 and v2 are inalignment with axis Z2Z2. In fact, any position in which stationaryelectrodes se2 is no longer overlapped by one or other of electrodes v1and v2 indicates a lead. This lead is, however, only detectable when oneof these mobile electrodes lies opposite stationary electrode sel. Insuch a position of disc k, a signal Vq impulse of negative potential isthen capacitively transmitted only to stationary electrode sel and henceto contact jl.

During the time intervals between the signal Vq impulses, capacitors C12and C13 discharge through the p-n junctions of contacts jl and i2 andcan become charged again when the associated transistors T19 and T20 areconductive.

Since mobile electrode v2 lies remote from stationary electrode se2,signal Vq impulse can reach neither junction j2 nor the gate oftransistor T19 so that this latter transistor remains blocked andcapacitor C12 remains in a discharged condition. This means that thissignal Vq impulse can reach the gate of transistor T22 to unblock thelatter whereas transistor T21 remains blocked because of the absence ofany voltage at its gate owing to transistor T20 being unblocked by thesignal Vq impulse.

Since transistor T22 is open, the signal Va21 impulses cannot reachtransistor T24 which remain blocked.

The impulses of signal Va20 cannot reach transistor T25 via capacitorC17 becomes at that instant transistor T27 is open, this open state ofT27 being due to the fact that its gate is receiving these same signalVa20 impulses via capacitor C14, transistor T21 being blocked.

This means that capacitor C16 remains discharged and that the controlcircuit of relay Rb cannot operate since the gate of transistor T26remains at zero potential thereby not enabling this transistor to beunblocked for current to flow through to the winding R6 of the relay.

In this way a relay actuating impulse Vm can be cut out to enable theaccidental lead that has been taken by the wheel train and that has beendetected to be wiped out.

(C) THE WHEEL TRAIN OF THE WATCH COMES TO BE LAGGING Should the wheeltrain of the watch come to be laging, disc k would come to lie, forexample, in a position such that its electrodes v1 and v2 are inalignment with axis Z3Z3. In fact, any position in which stationaryelectrode sel is no long overlapped by one or other of electrodes v1 andv2 indicates a lag. This lag is, however, only detachable when one ofthese mobile electrodes lies opposite electrode se2. In such a positionof disc k, a signal Vq impulse of negative potential is thencapacitively transmitted only to stationary electrodes se2 and henceonly to contact j2.

As before, capacitor C12 and C13 discharge through the p-n junctions topoints '1 and 12 during the time intervals between the signal Vqimpulses, these capacitors only being rechargeable when their associatedtransistors T19 and T20 are conductive.

Since mobile electrode v1 lies remote from stationary electrode sel. Vqimpulse can reach neither junction '1 nor the gate of transistor T20 sothat this latter transistor remains blocked and capacitor C13 remains ina discharged condition. This means that this signal Vq impulse can reachthe gate of transistor T21 to unblock the latter whereas transistor T22remains blocked because of the absence of any voltage at its gate owingto transistor T19 being unblocked by the signal Vq impulse.

Since transistor T22 is blocked, the signal Va21 impulses can reachtransistor T24 which then becomes conductive in phase with theseimpulses.

Since, moreover, transistor T21 is conductive throughout the duration ofthe signal Vq impulse, the signal Va20 impulses cannot reach transistorT27 as long as electrode q is receiving signal Va impulses so that thistransistor T27 remain blocked. This means that these same signal Va20impulses can then reach the gate of transistor T25, via capacitor C17,which transistor is thusalternate- 1y opened and closed at the frequencyof the signal Va20 impulses.

As may be seen from the FIG. 11 diagram, transistor T25 is placed in aposition equivalent to that of transistor T24, i.e. in parallel withcapacitor C16, so that it can, upon being opened, cause the discharge ofthe latter in the same way that transistor T24 can upon becomingconductive.

Since the impulses of signal Va20 have a frequency twice that of theimpulses of signal Va21 and since this latter signal is derived from thefirst, the two signals are consequently in phase (FIG. 12).

When the impulses of these two signals Va20 and Va21 appearsimultaneously, transistors T24 and T25 become conductive at the sametime also and cause capacitor C16 to discharge under conditionspractically identical to those that prevail when only one of thesetransistors is conductive. The relay is actuated quite normally by asignal Vm" impulse having characteristics very similar to those of thesignal Vm impulses being produced at a frequency of 1 c./s. when thewatch is working correctly.

When the other signal Va20 impulses appear, stage EC21 produces nosignal V1121 impulses so that only transistor T25 becomes conductive.This results in the production of an additional relay-actuating signalVm impulse, which impulse is thus fitted in between two normalrelayactuating signal Vm impulses.

One impulse has thus been added to the 1 c./s. impulse train and thisextra impulse makes it possible to correct the position of the wheeltrain by an amount corresponding to the pitch thereof.

The device for correcting the position of the wheel train, whosecharacteristic features have just been described, thus enables arelay-actuating impulse to be cut out or to be added in order to make upfor a lead or a lag detected by the Wheel train coincidencediscriminator in the course of each checking period, which periodcorresponds to the length of time a signal Vq impulse is applied toelectrode q.

According to a modified constructional form which has not beenillustrated, the disc k that is visible in FIG. 11 could be providedwith only one mobile electrode v and the stationary electrodes sel andse2 could then be arranged on opposite sides of a common axis at adistance therefrom corresponding substantially to half the width ofelectrode v. This axis constitutes the reference position in whichelectrode v should come to be located periodically, i.e. at thefrequency of the signal Va26 impulses, if the time given by the watch isaccurate, i.e. if this indication effectively corresponds to the countmade by relay Rb of the signal Va21 impulses that have issued from thedivider.

In such an event, a signal Vq impulse that has capacitively beentransmitted to the mobile electrode v could be passed on neither to thestationary electrode sel, nor to the stationary electrode se2. Thismeans that the relayactuating circuit Rb is being normally supplied withsignal V1121 impulses.

1f mobile electrode v receives a signal Vq impulse before reaching thisreference position or when it has al ready moved past it, this indicatesthat the wheel train is lagging or leading, as the case may be, inrelation to the exact position it should be occupying at that instant.In the first case, mobile electrode v lies opposite only stationaryelectrode se2 and in the second case it lies opposite only stationaryelectrode sel. Consequently, a correction signal Vq impulse iscapacitively transmitted to only one of these electrodes as was the casein the FIG. 11 construction. A lead or a lag that has been detected inthis way can be corrected by means of an electronic arrangement similarto that illustrated in this figure and in a similar manner.

It may further be added that, in order for the control voltages fortransistors T21 and T22 to be maintained for relatively long checkingperiods, it would be possible to modulate signal Vq by means of a highfrequency signal which is for instance taken from the output of one ofthe divider stages EB2 to EB11 (FIG. 4), and to use this modulatedsignal to perform periodic recharging of the input capacitance of thesetransistors by means of a suitable circuit, e.g. similar to that formedby the transistors Tc3 and T05 and by the capacitor C03 in the EC stageillustrated in FIG. 7.

Although, in the foregoing description, reference has only been made tothe possibility of checking and correcting, in an electronic watch, theway in which a wheel train driven by a monostable relay is working, theabove described principles are clearly also applicable to watches havinga bistable relay or even an electromechanical converter of any otherkind provided that the electronic circuits of the watch, which enable,in particular, control of the converter and correction of its operation,are adapted to suit the particular manner of operation of the converterthat is resorted to.

What is claimed is:

1. An electronic timepiece comprising a time base delivering highfrequency electric signals; electronic means for dividing said frequencywhich include a succession of dividing stages; a time-indicating devicewhich includes time-representing members and which is controlled by thesignals of divided frequency issuing from the dividing means; and atime-setting device; wherein is provided a correcting device whichincludes means for periodically detecting any positional deflection ofsaid time-representing members in relation to a reference positioncorresponding to that which these members should be occupying at theinstant of detection on the basis of a count of the signals issuing fromthe dividing means for producing a signal indicative of the direction ofsaid deflection, means for momentarily connecting the timeindicatiugdevice to an intermediate stage of the dividing means, when saidindicative signal indicates a lag on the part of said time-representingmembers, thereby to accelerate the operation of said device to make upsaid lag, and means for momentarily interrupting all connection betweenthe dividing means and the time-indicating device, when said indicativesignal indicates a lead on the part of said time-representing members,thereby to cut out this lead through stoppage of said device.

2. A timepiece as claimed in claim 1, wherein said correcting devicefurther includes a first information channel for receiving saidindicative signal when it indicates a lead on the part of saidtime-representing members, and a second information channel forreceiving said indicative signal when it indicaties a lag on the part ofsaid timerepresenting members, wherein said connecting means include afirst electronic switch associated with said first channel and adaptedto be controlled by the signal travelling along said first channel, andwherein said interrupting means include a second electronic switchassociated with said second channel and adapted to be controlled by thesignal travelling along said second channel.

3. A timepiece as claimed in claim 2, wherein said detecting meansinclude a source delivering checking signals having a frequency lessthan that of the signals issuing from said dividing means, first andsecond stationary electrodes respectively connected to said first andsecond information channels and disposed on opposite sides of ageometrical axis defining said reference position, said stationaryelectrodes serving to detect the possible presence of at least onemobile electrode kinematically associated with said time-representingmembers and arranged to travel along a circular path past saidstationary electrodes and to receive said checking signals from saidsource, the initial angular position of said mobile electrode and thespeed at which it moves being so selected that, each time said sourcedelivers a checking signal, said mobile electrode comes to be located insaid reference position when the time shown by said timerepresentingmembers is the same as that it should actually be on the basis of saidcount of the signals of divided frequency issuing from said dividingmeans, and comes to be located ahead of, respectively behind, saidreference position, opposite a corresponding one of said stationaryelectrodes, when the time shown by said time-representing members isfast, respectively slow, in relation to the time corresponding to saidcount of the signals issuing from said dividing means.

4. A timepiece as claimed in claim 2, wherein said detecting meansinclude a source delivering checking signals having a frequency lessthan that of the signals issuing from said dividing means, said sourcebeing connected with a pair of diametrically opposite electrodes carriedby a rotary support which is kinematically associated with saidtime-representing members and which is arranged to rotate through 180during the time interval between two successive checking signals whenthe time shown by said time-representing members is the same as that itshould actually be on the basis of said count of the signals of dividedfrequency issuing from said dividing means, and to rotate though more,respectively less, than when said time-representing members indicate alead, respectively a lag, in relation to the time corresponding to saidcount of the signals issuing from said dividing means, said detectingmeans further including, for detecting the position of said mobileelectrodes, first and second stationary electrodes which arerespectively connected to said first and second information channels andwhich extend, along the circular path followed by said mobileelectrodes, each over a length corresponding to at least two successiveintermittent displacements on the part of said mobile electrodes and ina relative position such that the leading end of said first stationaryelectrode, in relation to the direction of rotation of said support,lies diametrically opposite the trailing end of said second stationaryelectrode, and wherein said rotary support is initially angularly sopositioned that, during rotation, said mobile electrodes carried therebycome to face each a corresponding one of said stationary electrodes uponreceiving said checking signal, when the time shown by saidtime-representing members is the same as that it should be on the basisof said count of the signals of divided frequency issuing from saiddividing means, this relative position of said mobile and stationaryelectrodes corresponding to said reference postion, and that only one ofsaid mobile electrodes comes to face a particular one of said stationaryelectrodes, ahead of or behind said reference position, when saidchecking signal reaches said mobile electrodes, depending on whethersaid time-representing members show a lead or lag in relation to thecorrect time.

References Cited UNITED STATES PATENTS 3,479,812 11/1969 Kramer 58-25RICHARD B. WILKINSON, Primary Examiner E. C. SIMMONS, Assistant ExaminerUS. Cl. X.R. 5 8-24

